Eh, I think it’s just about ease of use and discovery. When you open a terminal, it just shows a blinking cursor. If you’ve never used the terminal before, how do you know what to type?

In a graphical desktop environment, you see icons, menus, etc. If you open a GUI application, you usually see buttons and things to click, and maybe even some guidance on how to use the app.

A lot of people just want to use their computer without too much of a learning curve. Most people are not powerusers.